sunderland



J. P SUNDERLAND.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED AUG. 1. 1911 1,304,624. Patented May 27, 1919.

4 SHEETS-SHEET l.

INVENTOR Q WW4 .4 TT ORNE Y J. P. SUNDERLAND.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED Aucm. 1912.

1,304,624. Patented May 27, 1919.

4 SHEETS-SHEET 2.

/N VEN TOR Qt$ x WMW BY MMM A TTORNEY J. P. SUNDERLAND.

ELECTRIC HEATING APPARATUS. APPLICATION FILED 'AUG.II. 1911.

1,304,624. Patented May 27, 1919.

4 SHEETS-SHEET 3.

mmvron A TTOR/VEY 1. P. SUNDERLAND.

ELECTRIC HEATING APPARATUS.

APPLICATION FILED AUG. I. 1917.

1,304,624. Patentd May 27, 1919.

4 SHEETS-SHEET 4.

INVENTOR A TTORNEY UNITED STATES 'PATENiT OFFICE.

JOHN P. SUNDEBLAND, or ALBANY, new YORK,

Assmnoa, BY manor AND MEBNE ASSIGNMENTS, TO GEORGE G. MILNE, OI BYE, NEW YORK.

nnncmc nm'rmo arrana'rus.

Specification 01 Letters Patent.

Patented May 27, 1919.

To all whom itmay concern:

Be it known that I, JOHN P. SUHDERI'AND, a citizen of the United States, and a resident 0f Albany, in the county of Albany and State of New York, have invented certain new and useful Improvements in Electric Heating Apparatus, of which the following is a specification.

My invention relates to electrical heating apparatus, and especially to apparatus for heating rivets by passing an electric current therethrough.

The main object of the invention is rovide an apparatus of this character wh1c is not only simple and efiicient 1n operation and construction, but by means of which rivets and the like may be very rapldly heated.

A further object is to provide an apparatus of the general character in question, which may be so operated that the rivets will not be burnt or overheated.

A further object of the invention is to provide an apparatus-by which the longer rivets may also beheated very rapidly and without danger of burning or overheating them.

Further objects, features and advantages will more clearly appear from the detail description given below, taken in connection with the accompanying drawings, which form a part of this specification.

In the drawings,

Figure 1 is aside view of an apparatus embodying my improvements in one form;

Fig. 2 is a plan view of the same, certain 4 parts being omitted or broken away to more clearly illustrate others;

Fig. 3 is a front end view of the same, certain parts being omitted to more clearly illustrate others;

Fig. 4 is a section on the line AA of Fi 2' K Fig. 5 is a section through the transformer, taken on the line BB of Fig. 2; and

Fig. 6 is a diagram illustrating diagrammatically the transformer connections and windings.

Referring to the various figures, 1 repreclearly indicated in Fig.

sents a base board on which is secured an insulating board or sheet of asbestos 2. Secured upon one end of the base is an electrical contact head of soft metal, such as copper, 3, extending along the front of the apparatus. Pivoted to the framework at 5 are two pairs of arms 4, in the ends of which are secured, respectively, electrical contact heads of soft metal, such as co per, 6, the heads being insulated from t e arms 4, which support them. Handles 7 are suitably secured to the arms 4, so that the heads 6 may be raised and lowered away from and toward the head 3 to permit the insertion of rivets 8 between the heads, with one end of each rivet abuttin the head 3 and. the other end of each rivet a uttin one of the heads 6.

9 represents a trans ormer, suitably secured to the base, and having bolted to the top thereof brackets 10, which may serve as handles for the apparatus. The primary of thetransformer consists of three sets of windings 11, 12 and 13, consisting of 100 turns each, of copper wire, wound upon a laminated iron 'core 14.- (see Fi 5). The secondary windings'of the trans ormer consist of four main turns 15, 16, 17 and 18. Each turn comprises a solid copper bar, bent to make one turn about the core 14. The upper ends of turns 15 and 17 are connected together by copper straps 19, the lower endsof turns 16 and 18 are connected together by copper straps 20, the upper end'of turn 16 is connected to the lower end of turn 15 by copper straps 21, and the upper end of turn 18 is connected to the lower end of turn 17 by copper straps 22. Bolted between the straps 19 are two sets of copper strap conductors 23. and 24, one-half of the straps 23 being bolted to the underneath side of one of the heads 6, and the other half of the straps 23 being bolted to the top of the head 6, as

1. Likewise, onehalf of the straps 24 are bolted to the underneath side of the other head 6, and the other half of the straps 24 are bolted to the upper side of the other head 6, so that each head6 is electrically connected to the upper ends of turns 15 and 17 through flexible connections. Bolted between the straps 20 are two sets of flexible electric strap conductors 25 and 26, which are similarly bolted to the lower head 3, half being bolted to the underneath side of said head, and half being bolted thereto on the upper ledge of the head, as clearly indicated in Fig. 1.

I also provide two extra secondary turns on the transformer, these turns being indicated at 27 and 28 (see Fig. 5)- The turn 27 lies adjacent the turn 15 and is in electric contact therewith substantially over its whole length. The turn 28 lies adjacent the turn 16,'but is insulated therefrom by insulating material 29. The upper end of turn 27 is electrically connected to the upper end of turn 28 by copper connecting straps 30. The lower end of turn 27 is connected to the lower end of turn 28 by connecting straps 31.

Surrounding the primary and secondary windings is a laminated magnetic structure of soft iron 32, the shape of the laminations being shown in Fig. 5. In this figure, the shape of the laminations of the core structure 1,4 is also shown.

The ends of the primary turns are brought out from the primary coils to a connectlon box 33.

Pivoted to a cross-bar 34 (see Fig. 2) are two sets of arms 35 and 36. Back of the to lever arms 43 and 44, respectively, so that,

upon depressing the lever arm 43 or 44, the

wedge-shaped member connected thereto will be forced between the inner ends of the arm 35 or 36 and cause the outer ends of the pair of arms to approach one another and engage the rivet 8 intermediate its ends, so

as to make an electrical contact with therivet intermediate its ends.

Bolted between the conductins straps 31 is a set of copper connecting straps 45, divided into four groups, the outer end-pf each group being secured to make electrlcal connection with the inner end of one of the arms 35 and 36, respectively (see Figs. 1 and 2).

Any suitable connections 46 may be made to the ends of the lever arms 43 and 44, so that these, arms may be depressed to cause the arms 35 and 36 to electrically engage the rivets therebetween, and likewise any suitable means may be provided to cause the arms 43 and 44 to be retained in their depressed oondition, so that the arms 35 and 36 will continue to en age their respective rivets during the heating thereof.

- In operation, the rivets are placed between the heads 3 and 6, and the head 6 lowered thereon so as to hold the rivets therebetween under pressure. In the machine shown, the pressure is about eight pounds.

Assuming the transformer to be energized, current then passes from the secondary terminals through the heads 3 and 6 and through the rivet, causing the rivet to be heated from its flat end down; that is, it becomes hottest at its flat end and the rivet gradually becomes softened from its fiat end downwardly or toward its head.

The heating of the rivet is caused by liberation of energy due to the opposition to the current. This opposition may be divided into two classes, that due to the contact resistance between the contact heads and the ends of the rivet, which depends upon the softness of the metal of the contact heads and the pressure applied, and that due to the effective impedance in the I rivet which may consist of ohmic resistance, hysteresls losses, eddy current losses, mductance and skin efi'ect losses. These vary materially with the shape and size of the rivet and the material from which it is made, and the nature of the current employed. In the apparatus described the contact resistance between the contacts and the ends of the rivet is such that the upper or flat end of the rivet heats faster than the shank or middle portion of the rivet. This appears to be due to a relatively large amount of heat liberated at this end at the point of contact, by the current overcoming the contact resistance. In this manner the heat is concentrated where it is needed most so that the final heating of the rivet is accomplished in a minimum time and with a minimum consumption of energy.

However, this is perhaps not the most important feature, because, if the end of the rivet is melted or burned by this so-called concentration of heat, it is not suited to be afterward inserted in the hole in the work because of the damaged end. Thisburning ing of the rivet at the end of the rivet adjacent the contact. Burned rivets are thrown away as scrap and even by the old methods of heating by coal or oil flame this loss is very large. I have found however, that by using a relatively low voltage this burning of rivets can be entirely eliminated without material loss in time in completing the heat. ing of the rivets. If an excessive voltage is used, so much heat is generated at the contact that it cannot be conducted into the body of the rivet fast enough to prevent local overheating and burning of the rivet at the ends. .To prevent burning with the apparatus described I may use an applied voltage of about 2 volts or slightly less. However the highest voltage which will not'burn depends not only upon thesize, shape and material of the rivet, and nature of the current but also upon the speed with which the contact heads conduct the heat away from the end of the rivetand the relative value 'ter electrica connection therewith, so that there is less contact resistance'at this head end and hence less generation of heat there due to the contact resistance. I find that some rivets have a small projection in the center of the head end, apparently produced in the forging of the rivet, and that when such rivets are heated accordin to my method, even less heat seems to generated 'b the contact resistance at the head end. ere the head end has a flat surface contacting with the electrical contact head,

substantially e ual in area to the area of the -ed from bot upper end of t e rivet, I find that the generation of heat at thelower end seems to be substantially equal to-the generation of heat at the u 'per end and the rivet is heatends inwardly. It will be understood that by suitable adjustment-of conditions the ratio between the effective internal im edance in the rivet and the contact resistances ma be such that all parts of the rivet will eat up equally fast or the center will heat up fastest, but the a heating of the end fastest has the important advantage that the rivet is heated sufiiciently for practical purposes in very much less time and with the consumption of much ess energy, considerations which are of great importance, speed bein an especially important factor in present ay commercial operation. The pressure exerted on the softened end of the rivet by the contact heads is, of course, insuflicient to displace the softened metal, as otherwise the rivetcould not be inserted in the hole for which it is designed.

If a long rivet is being heated, it is desirable to make use of the third contact device .or devices 35 and 36, in which case lever arm 43 is depressed, causing extra current, generated in the secondary turns 27 and 28, to be passed through the upper end portion of the rivet, so as to more quickl heat that portion of the rivet which is desired to be heated and without burning the rivet,-that is, causing it to become too soft at the end that is to be upset later.

Suitable switching apparatus is provided as shown in Fig. 6, whereby the number of turns of primary windings may be varied,-

thatis, some of the turns may be cut out.

For that purpose, a switch 50 is provided,

.1 inch long, I

heating current is flowing I .3 or .4 volt lower than the to cause it to beheated and so ondary is open-circuited.

It will be noted that the four main secondary turns are connected in pairs,two pairs in parallel, and two pairs inseries.

When heating rivets 1 inch in diameter by referably use the 300 turns of primary win lngs, and when so connected the calculated voltage on the secondary with the secondary open-circuited is about 1.4 volts.

With rivets inch diameter by 11} inches long, I preferably cut out part of the primary turns, so as to use onl 275 primary turns, thus producing a calc ated open-circuit secondary voltage of about 1.6 volts.

When heating rivets '1; inch diameter by 24} nches long, I preferably use about 200 turns 1n the primary and a calculated open-circult secondary voltage of about 2 volts.

'If a :2 inch diameter by 3 inches long' rivet is being heated, I preferably increase the open-circuit secondary voltage to about 2.5 volts, and if a inch diameter by 1% inches long rlvet is being heated, I preferably lncrease the calculated secondary voltage to about 3.5 bolts. 3

If, however, a voltage materially higher than the above values is used in the above described machine shown in the drawings I find that the rivets are apt to be burnt. 6n the other hand, it is desirable to use as great a voltage as is advanta ms, in order that thbe1 rivets may be heated as quickly as poss1 e.

I find that the smaller size rivets may be heated more quickly and without burning by applying a voltage of about 2 volts (actual yoltage applied with heating current flow-.

be in circuit, and when maintained. The voltage a gplied when the nd to be about calculated open described appa When long rivets are used, such as 21- inches or over, I preferably make use of the thirdcontact devices 35 and 36, so that the additional current is sent throu h the rivet fiened down rapidly and withcircuit voltage in the above ratus.

to the desired extent more out burning the rivet.

I With the above apparatus, I am enable d to heat rivets in from 3m 60 seconds with- 6 volts. Thus, the transformer should be so designed and wound orthe source of electric;

current be so selected and connected to send a current through the heads and r vet of such size as to heat the rivet soft the reuired distancewithout burning the end of I .t e rivet.

prevented.

While I prefer to use alternating current as energizing means, certain of myimproveinents may befound advantageous in case a direct current is used.

At the ends of the core 14,1 provide airspaces 60 filled with shellac, so that, in case the secondary should become short-circuited,

flow of excessive secondary current will be It is not necessary,"to the broader aspects of my invention, that the apparatus be provided with two heads 6, but I find that if a plurality of heads 6, with cooperating head or heads 3, is prov'ided,supplied from the same source or transformer if desired, and in parallel if desired, aplurality of rivets may be heated simultaneously. I find that,

even although such plurality of rivets may.

be inserted simultaneously, one will always become heated before the other, so that the operator may. insert and remove the rivets alternately, and thus greatly increase the. speed with which rivets may be heated by'the apparatus.

As shown in the drawings, only one head 3 is provided, but this is equivalent to two heads, as one portion cooperates with one head 6 and the other portion cooperates with the other head 6.

Since the third contact device 35 is connected to secondary windings on the transformer,.which embrace only. two turns in parallel, the voltage applied between the contact devices 35 and 36 and the head 6 in great detail in respect to an apparatus embodying them, in one form, I do not desire to belimited to such details, since many changes and modifications may be made without departing from the spirit and scope of the invention in its broader aspects. I

desire to cover all forms of apparatus coming within the'language of thejappended claims.

What I claim is:

1. An apparatus .of the class described having in combination a transformer with its primary and secndary, a plurality of contact heads connected to one terminal of v tively. 2. An apparatus of the class described havin in combination a transformer with its primary and secondary, a plurality of contact heads connected to one terminal of the secondary and a single or common contact head connected with the other terminal of the secondary and adapted to cooperate with each of the first mentioned contact heads to conduct current through the work placed between said contact heads respectively, and means for independently moving the first mentioned contact heads toward and away from said common head.

3. An apparatus of hev class having in combination a transformer with its primary and secondary, a plurality of .contact means, flexible conducting straps connecting said means with one terminal of the secondary and in parallel with one another, contact means forming an electrode means opposing said first contact means and electrically connected to the other terminal of the secondary, and means for independently moving said first contact means sub- .stantially for the purposedescribed.

4. An apparatus of the class described having-in combination a transformer with its primary and secondary, a plurality of contact heads, flexible conducting straps connecting said heads with one terminal of the secondary, a stationary contact forming an electrode means opposing said contact heads and electrically connected to the other terminal of the secondary, and means for independently moving said contact heads substantially for the purpose described.

5. In an electric rivet heating apparatus,-

described the combinationof a plurality of pairs of electrical contact heads between each pair of which a rivet is adapted to be placed with one of its ends abutting one head of the pair and the other of its ends abutting the other head of the pair, said heads having substantially flat faces where they abut the rivets, a source of electriccu-rrent, and con nections from said head'sto .said source and means for moving the heads of one pair toward one another independently of theheads of another pair.

7. In an electric rivet heating apparatus or the like, the combination of a plurality of pairs of electrical contact means between each pair 0 of which a rivet or the like is adapted fobe placed with one of its ends abuttin one contact of'the pair and another part 0 the rivet or the like being connected to the other contact means of the\ pair, a source of electric current, and connections from said contact means to said source, one contact means of each pa r beingmovable away from and toward the other V contact means of the pair to permit insera tion of the rivet or thelike between the contact means of the pair independently of the Y contact means of another pair.

8. An apparatus of the class described having in combination two op osing contact heads adapted to contact wlth .the ends of a rivet respectively, said heads having substantially flat faces where they make con- 0 tact with the rivet and being of relatively softmetal whereby the contact resistance with the head of the rivet is relatively low, and a source of electric current connected to said contact heads.

9. An apparatus of the class described havin in combination a transformer with its prlmary and secondary, a plurality of contact heads, flexible conducting straps consubstantially flat faces where they make contact with the rivet and being of relatively soft metal whereby the contact resistance with the head of the rivet is relatively low, a source of electric current connected to said contact heads, and means causi the contact heads to engage-the rivet with a predetermined pressure.

11. An apparatus of the. class described. having in combination two opposing contact heads adapted to contact with the ends of a rivet respectively, said heads having substantially fiat faces where they make contact with the. rivet, means causing the contact heads to engage the rivet with a predetermined pressure and incapable of displacin the heated metal of the rivet, and a source 0 tact means makin electriccurrent connected to saidcontact heads.

1 2. In an electric rivet heater-'or the like .the combination of a contact head having a substantially flat face adapted to contact with the flat end of the rivet or the like, con- I contact with the other part of the rivet with less contact resistance, means causing the contact head to engage the rivet with a predetermined pressure and incapable of displacingthe heated metal of the rivet, and a source of electric current connected to'said contact head andpontact means for the purpose described.-

1 3. In an electric rivet heating apparatus or the like, the combination of means for sending current through the rivet or the like from end to end and means for sending additional current througnone end portion of the rivet or the like. I

' 14. In an electric rivet heating apparatus, the combination of two electrical contact heads between which the rivet is adapted to be placed with one end of the rivet contacting with one head and the other end of the rivet contacting with the other head, and an electrical contact device adapted to contact with the rivet intermediate its ends.

15. In an electric rivet heating apparatus or the llke, the combination of two electrical contact means between which the rivet is adapted to be placed with one endof the rivet or' the like contacting with one means a and the other end of the rivet or the like contacting with the other means, an electrical contactdevice adapted to contact with the rivetor the like intermediate its ends, and means applying a potential difference between said contact means, and means connecting said electrical contact device with a source of electrical energy to apply a less difference of potential to the rivet or' the like betweenone of the contact means and said electrical contact device.

16. In an electric rivet heater the combination of a contact head having a substantiall flat face adapted to contact with the smal end of the rivet, contact means making contact with the other end ofthe rivet, means causing the contact head to engage the rivet with a predetermined presj sure and incapable of displacing the heated metal of the rivet, and a source of electric current connected to said contact head and contact means for the purpose described.

17. In an electric rivet heating a paratus,

the combination of two electrlca contact heads between which the rivet is adapted to be placed with one end of the rivet contacting with one head and the other end of the rivet contacting with the other head, an electrical contact device" adapted to contact with the rivet intermediate its ends, and

means for moving said electrical contact device into and out of contact with the rivet.

18. In an electric rivet heating a paratus, .the combination'of two electrlc contact I heads between which the rivet is adapted to be placed with one end of the rivet contact-v ing with one head and the otherend of the rivet contacting with the other head, one of said heads being movable with respect to the other head, a transformer havmg its secondary connected to said heads, an electhe case in the Patent Ofiicei [sEALJ Gorrection in LetterePatent v.No. .1 304,624, 5.

means causing the contact'head-to engage the rivet with a predetermined pressure and nected to said contact head and contactmeans for the purpose described.

20. In an electric heating a paratus of the class described, the combination of two electrical contacts and means connected thereto adapted to send a current throughthe article to be heated and a third contact with means connected thereto adapted to increase the current through a part of the article to be heated. v

. Signed at New York in the county of New York and State of New York this 30th day of July A. D. 1917.

JOHN P. SUNDERLAN D.

Signed and sealed thiaSth'glay oi 'iiluly, D., 1919,.

R. F WHITEHEAD, Acting Uommissiomr of Patents;

- It is hereby certified that in Letters Patent N 0; 1,304,624, granted May 27, 1919, i

the applications; John "P. Sunder-land, of Albany, New York, for i provement in- Electric Heating Apparatus, an error appears inthe i ted specification requiring correction as follows: Page 5, line 96, claim 15, after the word rivet insert the words or t hc li ke, and that the said Letters Patent should" be-read with this correction therei nlithat the same may conform to the record of 

